Structural honeycomb material



Oct. 28, 1939 o. D. WHITE 3,475,252

STRUCTURAL HQNEYCOMB MATERIAL Filed Nov. 2?, 19'64 United States Patent3,475,252 STRUCTURAL HONEYCOMB MATERIAL Desmond Deverell White, Radlett,England, assignor to Dufaylite Developments Limited, a British companyFiled Nov. 27, 1964, Ser. No. 414,065

. Int. Cl. B26d 5/08; B321) 31/00 US. Cl. 156-353 2 Claims ABSTRACT OFTHE DISCLOSURE US. Patent No. 3,166,456 of White, Thwaites and Judddescribes apparatus for making structural honeycomb material in which aweb of sheet material is formed with equally spaced transverse rows ofcolinear slits, which slits leave therebetween portions of intactmaterial which act as hinge formations. The thus perforated web is feddownwardly onto a support where it folds automatically concertinafashion. Between being perforated and reaching the support the Web hasapplied to both sides thereof longitudinally extending bands ofadhesive, the bands on one side of the web being staggered with respectto the bands on the opposite side thereof. Thus, in the concertinafolded material the glue bands are in the correct position for themanufacture of structural honeycomb material. Excellent results havebeen obtained in this manner. a

The present invention is concerned with the apparatus for producing therows of transverse slits. In the apparatus the web passes around theperiphery of a rotating drum, and the drum is provided with a toothedretractable blade. Means, for example pneumatic rams, are provided onthe drum for forcing out the blade so that the teeth project from theperiphery of the drum in a stabbing motion. Each tooth penetrates thepaper and forms one of the slits.

Prior methods of forming slits in the travelling web have involved theuse of rotating drums carrying fixed blades which press the paper on toanother drum-see for example US. Patent No. 3,166,456 of D. D. White(the present applicant) et al. A fixed blade is found to give unreliableresults and even to fail frequently in its operation. In contrast theblade of the present invention with its stabbing action functions.reliably and effectively.

The present invention relates to the production of structural honeycombmaterial and has as an object the provision of improved apparatus andmethods therefor.

In the Patent No. 3,166,456 of Desmond Deverell White, Peter JohnThwaites and Geoffrey Ronald Judd there is described a method for theproduction of structural honeycomb material which comprises applying wetbands of adhesive to both faces of a web of bibulous sheet material inpositions such that the bands applied to one face are staggered withreference to the bands applied to the other face, feeding the webdownwardly towards a support and folding it backwards and forwards uponthe support so that it is accumulated upon the support in the form of astack of layers which are adhered together by the wet hands and areinterconnected at their ends, characterised in that the web is formed atequidistant intervals along its length and thereby divided into discretesheet sections, with hinge formations, and is fed downwardly to thesupport at a rate of feed such that it swings freely backwards andforwards under the reaction of the support and is accumulated in theform of a stack of layers in which each layer is constituted by one ofsaid sheets and the sheets are joined together by folds at the positionof the hinge formations. There is also described apparatus for carryingout this method, which apparatus comprises means for forming atravelling web of bibulous sheet material at equidistant intervals alongits length with hinge formations, adhesive applying means Patented Oct.28, 1969 for applying wet bands of adhesive to both of the faces of thetravelling web in positions such that the bands applied on one face arestaggered with reference to the bands applied to the other face, and asupport positioned to receive the web bearing the wet adhesive whilstthe web swings freely over and descends to the support. As shown in thesaid application the hinge formations are preferably sets of colineartransverse slits which leave the sheets joined together by interveningsections of intact material.

In accordance with the present invention there is provided animprovement in or modification of the said apparatus in which there isprovided a device for perforating the web material to form the sets ofcolinear transverse slits, which device comprises a roller carrying atleast one perforating tool mounted to be driven between a retractedposition and a position in which it projects from the peripheral face ofthe roller whilst the roller is being rotated.

In the application of the device, the web material is moved over theroller in such a manner that it is supported in rolling contact over asubstantial area, the perforating tool being driven between itsretracted and projecting positions to perforate the material whilst itis supported in this way. As the tool and the web move together with theroller and at the same speed, the perforating operation is achievedwithout interrupting the motion of the web. This is advantageous notonly because the need to provide complex feeding arrangements is avoidedbut also because the smooth continuous motion of the web avoids jerkingthe perforated material and so allows such forms of perforation asdivide the material into weakly interconnected sections to be providedin a reliable manner.

In a preferred arrangement the tool is driven by fluid operated,preferably pneumatic, actuators carried by the roller. Such actuatorsare readily arranged to produce a rapid stabbing motion of the toolwhich is found to be beneficial in that it minimises the tendency of theweb material to be pushed away from the former. A cam induced motion forthe tool tends to consume considerable power when arranged to give astabbing action.

The device is found to be capable of providing perforations in aremarkably accurately positioned manner provided that precautions aretaken to prevent slipping of the web material at the face of the former.In one convenient and very simple arrangement for this purpose theroller is provided with a pair of pinch rollers preferably faced withrubber or other flexible material for holding the web in contacttherewith. It is found that by driving the second pinch roller, that isthe roller at which the web leaves the roller, and allowing the firstpinch roller to idle a satisfactory drive for the drum is obtained;moreover the arrangement will readily draw the web material from anundriven or even braked supply roll, no take-off rollers being required.The accuracy of performance of the apparatus is found to be improved ifthe perforated material is maintained under light tension after leavingthe former. I

In order to illustrate the invention there is given the followingdescription of a preferred embodiment of the perforating deviceinstalled on a machine for the manufacture of structural honeycombmaterial. In the said description reference is made to the accompanyingdrawing in which:

FIGURE 1 is a perspective drawing showing the perforating device and theprinting rollers of the machine,

FIGURE 2 is a cross section taken on IIII of FIG- URE 1,

FIGURE 3 shows a part of the perforating tool, and

FIGURE 4 is a diagrammatic drawing which shows the manner in which theperforated and printed web is formed into honeycomb material.

In the perforating device shown in FIGURE 1 a drum 1 is formed with alongitudinal radial slot 3 along its whole length. Any convenientconstruction may be employed and in the case illustrated the drum wasformed by assembling a series of circular discs cut from woodenblockboard and machining the surface truly cylindrical. The grainpattern over the periphery of the drum gave a surface providing a usefulamount of friction with rough surfaced paper when used as the webmaterial. The axle 5 of the drum is hollow and is connected via arotational pressure coupling with a source of compressed air (notshown). On each end of the drum is mounted a pneumatic ram one of which7 is shown in FIGURE 1. The ram 7 is energized from the axle 5 via avalve 9, the plunger 11 of which is operated by a stationary cam 13. Asimilar valve and cam arrangement is provided for the ram at the otherend of the drum. Carried by the rams within the slot 3 is a perforatingtool 15 in the form of a plate profiled at its radially outermost sideto provide a series of uniformly spaced triangular teeth 17.

In a modified arrangement giving improved mechanical symmetry, the toolis carried, at each end of the drum by a bridge member operated by apair of rams.

For pressing the web material 19 into firm driven contact with the drum1 there are provided a pair of rubber faced pinch rollers 21 and 23operated by pneumatic rams 25. These rams force the pinch rollers intocontact with the web material and also serve for holding them clear whenthreading the web material. Roller 21 is driven from an appropriatemotor.

As the drum 1 rotates Web material is drawn from the supply roll 27 topass without appreciable slip over the peripheral surface of the drum 1.During its passage be tween rollers 23 and 21 the tool 15 is pushedoutwardly in a stabbing movement by its pneumatic rams under the actionof the cams to provide a series of colinear slits 29 separated by shortresidual sections 31 of the material. The tool is retracted by theaction of the cams before reaching the roller 21. If desired there maybe provided an axle carrying a series of discs running in contact withthe drum to support the portions 31 of the material during the stabbingaction, but this complication has been found unnecessary for themanufacture of honeycomb material from stout paper.

conventionally arranged printing rollers 33 and 35 are positioned belowthe pinch roller 21 for the application of continuous bands of adhesiveto opposite faces of the perforated material, those on one face beingpositioned between those on the opposite face. The adhesive bearingmaterial on leaving the rollers descends to a support 37, FIGURE 4.Provided that the distance between the roller 35 and the support 37 iscorrectly chosen, the material swings to and fro under the reaction ofthe support, folding at the positions of the slits 29 to provide a block39 of lightly adhered honeycomb which, after consolidation underpressure, may be cut into expandable slices.

The accuracy of perforating is such that a neat registration of folds isobtained at the ends of the block. The trimming waste of material istherefore trivial.

I claim:

1. In an apparatus for the production of structural honeycomb materialwhich comprises means for support.- ing a traveling web of bibuloussheet material, adhesive applying means for longitudinally applying wetbands of adhesive to both faces of the travelling web in positions suchthat the bands applied on one face are staggered with reference to thebands applied to the other face, support means positioned to receive theweb bearing the wet adhesive while the web swings freely thereover anddescends to the support, a device for perforating the traveling web toprovide said travelling web with hinge formations in the form of sets ofcolinear transverse slits at equidistant longitudinal intervals so as toleave the material of the web between said slits intact, said devicecomprising a roller carrying at least one blade having a series of teethfor forming said slits, said blade being mounted to be driven between aretracted position and a position in which it projects from theperipheral face of the roller while the roller is being rotated andfluid operated actuators carried by the roller for driving the bladebetween said positions.

2. In an apparatus for the production of structural honeycomb materialwhich comprises means for supporting a travelling web of bibulous sheetmaterial, adhesive applying means for longitudinally applying wet handsof adhesive to both faces of the travelling web in positions such thatthe bands applied on one face are staggered with reference to the bandsapplied to the other face, support means positioned to receive the webbearing the wet adhesive while the web swings freely thereover anddescends to the support, a device for perforating the travelling web toprovide said travelling web with hinge formations in the form of sets ofcolinear transverse slits at equidistant longitudinal intervals so as toleave the material of the web between said slits intact, said devicecomprising a roller carrying at least one blade having a series of teethfor forming slits, said blade being mounted to be driven between aretracted position and a position in which it projects from theperipheral face of the roller while the roller is being rotated,actuators for driving the blade between said positions, an idling pinchroller for bringing the travelling web into contact with the bladecarrying roller and a driven pinch roller for driving the web and theblade carrying roller, said driven pinch roller cooperating with theidling pinch roller to hold a section of the web in contact with thecircumference of the blade carrying roller.

References Cited UNITED STATES PATENTS 1,704,186 3/1929 Gammeter l56-256XR 1,988,640 1/1935 Welsford 156-253 XR 2,754,023 7/1956 Sheridan l56564XR 3,159,518 12/1964 Benton 156510 XR 3,166,456 1/1965 White et al.l56197 HAROLD ANSHER, Primary Examiner J. C. GIL, Assistant ExaminerU.S. Cl. X.R.

